In 1976 the Oxford ethologist Richard Dawkins published a book that would become one of the most popular and most influential science books of the 20th century: The Selfish Gene. It portrayed organisms in a very counter-intuitive way, as means or survival machines of genes, and particularly emphasized that genes and not groups or organisms are the fundamental units of selection. I investigate this genecentric and gene selectionist perspective on life from a multidisciplinary, diachronic (i.e., history and future) and philosophical angle. Its roots must be situated in the 19th century, more particularly in the work of the German biologist August Weismann, one of the founding fathers of modern biology, as briefly pointed out by Dawkins (1976, p. 11) himself. This begs the question: why did it take so long before this view on life was made explicit and, to a certain extent, elaborated? And why was it, ultimately, elaborated in a book about the sociobiology revolution (i.e., The Selfish Gene). Another question is: how can be explained that this historically deeply rooted view is so vilified by so many modern philosophers and biologists? In answering these and other questions, I propose and develop a view on the genecentric revolution in our understanding of life that sheds new light on a wide array of age-old topics in the history and philosophy of the life sciences, ranging from the historical position of Mendel (the so-called father of genetics) to the nature/nurture question and the project or dream of an integrated, evolutionary science of man.